An assumption is made that 'design' can draw from knowledge of 'art' at one extreme of its spectrum and science at the other. Designers are in a unique position to synthesise such knowledge and externalise it in the form of artifacts. 2D and 3D design include aspects of static art and therefore it follows that since 4D Design focuses on dynamic form it can incorporate knowledge of 'kinetic art', and particularly the performing arts at one extreme and dynamics within engineering science at the other.

In addition, there are many activities involving time-based design which are currently on the fringes of professional design. As information becomes more of a commodity and the value of the service industry increases, the way such information and service products are designed and delivered is increasingly important.

The classification of design activities under 2D, 3D and 4D design does not necessarily affect professional names such as industrial design, although it might be beneficial to use the terms more and highlight the obvious characteristic and therefore identity of various professional design activities.

The origins of Industrial Design are in 3D design but it can be considered 4D Design where there is both complex functional and kinaesthetic movements and interactions involved. However, the notion of a 4D product design extends far beyond the contemporary conceptual basis of established design professions, which have focused upon the design of material form for 'manufacture'. 4D Design involves much more.

Computer based designs and models do not necessarily involve 4D design. For example 3D computer models are just that - 'virtual' 3D, and if they move they are 'virtual' 3D animations. Even when there is some 4D design it is often poor. For example 4D design is often conspicuously lacking in computer games, as many superb 2D graphics and 3D modelled characters are not supported by imaginative and careful 4D 'game play design'. Likewise many multimedia applications often have attractive 2D screen designs on well designed 3D personal computers but the 'navigation' and level of 'interactivity' are poor due to naive 4D design .

Real 4D products have 'dynamic' form in real or actual space and can be events:

- at one extreme, the 'have a nice day' etiquette of employees in supermarkets,

- and the way food is served in restaurants eg. McDonalds vs The Ritz.

- through to 'customer care' systems in hotels, eg. a motel vs a Hilton.

- to the exotic mind products of New-Age enthusiasts ; or

- from the dynamic lighting designs in a discotheque or office using computer control technology

- to the 'staging' of Rave concerts;

- from the Fire Alarm that shouts "FIRE on the first floor"

- to the TV Knight-Rider car and 'talking' lift with 'personality',

- from the 'smart' focusing of a domestic video camera

- and automatic doors that open as you approach.

- to solar heat collectors that create imaginative visual effects on buildings as they follow the path of the sun across the sky using robotics technology.

If the teapot of the Japanese tea ceremony 'Chado' 'performed' along with the tea maker using animatronics technology then it too would involve 'real' 4D Design. Where there is a high cultural content of dynamic artistic expression based upon performing arts knowledge this kind of 'kinetic' design might be referred to as 'product opera' - opera signifying the integration of the time-based arts within a 4D product design, in contrast to the functional perspective taken to tasks in product design incorporating human factors/ergonomics data.

A comprehensive corporate identity design - the personality of a company and its interactive behaviour with people is a 'real' 4D design. Companies depend much on the success of how the organisation and its people behave to their customers.

An emphasis on real 2D and 3D design is placed in the design journals. Within architecture and interior design it is rare to see people in the glossy pages illustrating 3D geometrical spatial designs. The buildings are decanted of people. Perhaps this is due to the use of static print medium. Likewise, in Museums covering design the 'object in a glass box' is still dominant, rarely do you see a 'working' exhibit. This neglect of 4D design runs deeper and would not be too obvious if some visualisation of use was outlined with a diagram showing interesting traffic flow of people within the spaces.

The aim of professional design services is to provide industry, commerce and society with well thought out solutions. Designing takes placeoften without professional design services. 4D designs are all around us but as the importance of dynamic form in the human constructed world is acknowledged, professional 4D design services will be increasingly required.

It has been suggested here that 4D Design is a useful notion for a new kind of professional design activity, not only related to information technology, but also to industries in the service sector of the economy, when culture is integrated into commerce, and where dynamic form and the behaviour of people with each other and artifacts requires designing. 4D Design helps to us to classify and to discuss certain types of designs, and it gives some new creative activities a 'home' within the design business, profession and design education.

The 21st century will introduce products undreamed of today just as in the 19th century the everyday products we take for granted were beyond the imagination of the best minds of the period. 4D design will be central to new products, which will be based upon well designed dynamic form.